10,218 research outputs found
Shuffle on array languages generated by array grammars
Motivated by the studies done by G. Siromoney et al. (1973) and Alexan-
dru Mateescu et al. (1998) we examine the language theoretic results related to shuf- fle on trajectories by making use of Siromoney array grammars such as (R : R)AG, (R : C F )AG, (C F : R)AG, (C F : C F )AG, (C S : R)AG, (C S : C S)AG and (C F : C S)AG which are more powerful than the Siromoney matrix grammars (1972)
and are used to make digital pictures
Pattern matching in compilers
In this thesis we develop tools for effective and flexible pattern matching.
We introduce a new pattern matching system called amethyst. Amethyst is not
only a generator of parsers of programming languages, but can also serve as an
alternative to tools for matching regular expressions.
Our framework also produces dynamic parsers. Its intended use is in the
context of IDE (accurate syntax highlighting and error detection on the fly).
Amethyst offers pattern matching of general data structures. This makes it a
useful tool for implementing compiler optimizations such as constant folding,
instruction scheduling, and dataflow analysis in general.
The parsers produced are essentially top-down parsers. Linear time complexity
is obtained by introducing the novel notion of structured grammars and
regularized regular expressions. Amethyst uses techniques known from compiler
optimizations to produce effective parsers.Comment: master thesi
Adjunct hexagonal array token Petri nets and hexagonal picture languages
Adjunct Hexagonal Array Token Petri Net Structures (AHPN) are re-
cently introduced hexagonal picture generating devices which extended the Hexag- onal Array Token Petri Net Structures . In this paper we consider AHPN model along with a control feature called inhibitor arcs and compare it with some ex- pressive hexagonal picture generating and recognizing models with respect to the
generating power
Iso-array rewriting P systems with context-free iso-array rules
A new computing model called P system is a highly distributed and
parallel theoretical model, which is proposed in the area of membrane computing. Ceterchi et al. initially proposed array rewriting P systems by extending the notion of string rewriting P systems to arrays (2003). A theoretical model for picture generation using context-free iso-array grammar rules and puzzle iso-array grammar rules are introduced by Kalyani et al. (2004, 2006). Also iso-array rewriting P systems for iso-picture languages have been studied by Annadurai et al. (2008). In this paper we consider the context-free iso-array rules and context-free puzzle iso-array rules in iso-array rewriting P systems and examine the generative powers
of these P systems
Sublinearly space bounded iterative arrays
Iterative arrays (IAs) are a, parallel computational model with a sequential processing of the input. They are one-dimensional arrays of interacting identical deterministic finite automata. In this note, realtime-lAs with sublinear space bounds are used to accept formal languages. The existence of a proper hierarchy of space complexity classes between logarithmic anel linear space bounds is proved. Furthermore, an optimal spacc lower bound for non-regular language recognition is shown. Key words: Iterative arrays, cellular automata, space bounded computations, decidability questions, formal languages, theory of computatio
Introducing the Concept of Activation and Blocking of Rules in the General Framework for Regulated Rewriting in Sequential Grammars
We introduce new possibilities to control the application of rules based on
the preceding application of rules which can be de ned for a general model of sequential
grammars and we show some similarities to other control mechanisms as graph-controlled
grammars and matrix grammars with and without applicability checking as well as gram-
mars with random context conditions and ordered grammars. Using both activation and
blocking of rules, in the string and in the multiset case we can show computational com-
pleteness of context-free grammars equipped with the control mechanism of activation
and blocking of rules even when using only two nonterminal symbols
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